Economic Importance for Humans: Negative

Some mammal species are considered to have a detrimental impact on human interests. Many mammals that eat fruit, seeds, and other types of vegetation are crop pests. Carnivores are often considered to be a threat to livestock or even to human lives. Mammals that are common in urban or suburban areas can become a problem if they cause damage to automobiles when they are struck on the road, or can become household pests. A few species coexist exceptionally well with people, including some feral domesticated mammals (e.g., rats, house mice, pigs, cats, and dogs). As a result of either intentional or unintentional introductions near human habitation, these animals have had considerable negative impacts on the local biota of many regions of the world, especially the endemic biota of oceanic islands.

Many mammals can transmit diseases to humans or livestock. The bubonic plague is perhaps the most well-known example. Plague is spread via fleas that are carried by rodents. Rabies, which can be transmitted among mammalian species, is also a significant threat to livestock and can kill humans as well.